The present invention is an improvement of an invention relating to an engaging device which is described and illustrated in our U.S. Pat. No. 5,446,948 the contents of which are incorporated herein by way of reference. The engaging device disclosed in U.S. Pat. No. 5,446,948 comprises a supporting part and an engaging part mounted on the supporting part for pivotal movement about two spaced apart axes between two stable conditions, one being an engaging condition and the other being a release condition. A portion of the engaging part disposed between the two axes is of resiliently compressible construction to accommodate movement of the engaging part between the two stable conditions and to urge the engaging part into one or the other of the two stable conditions. Compressive stresses are induced into said portion of the engaging part as the engaging part moves between the two stable conditions thereby to urge the engaging part towards one of or the other of the two stable conditions with a snap-action. The two pivot axes about which the engaging part pivots are permanently fixed against lateral displacement with respect to each other during movement of the engaging part between the two stable conditions. The engaging part comprises two spaced arm portions and an elongated bridge portion extending between the arm portions. The arm portions are each mounted on the supporting part for pivotal movement about a respective one of the pivot axes between a first position corresponding to said release condition. With this arrangement, the bridge portion provides said portion disposed between the pivot axes. The bridge portion is resiliently bendable in two mutually perpendicular directions to provide the resilient compression. The two mutually perpendicular directions comprises a first direction generally parallel with the pivot axes and a second direction being in the direction of movement of said bridge portion as the engaging part moves between the two stable conditions. The bridge portion is provided with a reduced section to accommodate the resilient deflection. The reduced section comprises a flexure point formed in the bridge portion.
While the invention disclosed in U.S. Pat. No. 5,446,948 performs satisfactorily, there is no control over the particular side to which the bridge portion deflects when undergoing resilient compression. In some instances the bridge portion may deflect laterally to one of its sides and in other instances it may deflect laterally to the other of its sides.
It would be advantageous in some applications of the engaging device to provide an arrangement in which the lateral side to which the bridge portion deflects when moving between the two stable conditions remains constant and predictable.
The present invention seeks to provide such an arrangement.